From 367939a72bfc18f195bb162411d5596a2087d7ec Mon Sep 17 00:00:00 2001
From: "Christian Holler (:decoder)" <choller@mozilla.com>
Date: Mon, 13 Nov 2023 20:31:43 +0000
Subject: [PATCH] Bug 1863729 - IPC Fuzzing: Add MOZ_FUZZ_DUMP_FILTER. r=truber

Differential Revision: https://phabricator.services.mozilla.com/D193063
---
 tools/fuzzing/ipc/IPCFuzzController.cpp | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/tools/fuzzing/ipc/IPCFuzzController.cpp b/tools/fuzzing/ipc/IPCFuzzController.cpp
index af640f764317..5b8865f85d33 100644
--- a/tools/fuzzing/ipc/IPCFuzzController.cpp
+++ b/tools/fuzzing/ipc/IPCFuzzController.cpp
@@ -1024,12 +1024,30 @@ UniquePtr<IPC::Message> IPCFuzzController::replaceIPCMessage(
     return aMsg;
   }
 
+  static bool dumpFilterInitialized = false;
+  static std::string dumpFilter;
+  if (!dumpFilterInitialized) {
+    const char* dumpFilterStr = getenv("MOZ_FUZZ_DUMP_FILTER");
+    if (dumpFilterStr) {
+      dumpFilter = std::string(dumpFilterStr);
+    }
+    dumpFilterInitialized = true;
+  }
+
   if (aMsg->type() != mIPCTriggerMsg) {
     if ((mIPCDumpMsg && aMsg->type() == mIPCDumpMsg.value()) ||
         (mIPCDumpAllMsgsSize.isSome() &&
          aMsg->Buffers().Size() >= mIPCDumpAllMsgsSize.value())) {
-      dumpIPCMessageToFile(aMsg, mIPCDumpCount);
-      mIPCDumpCount++;
+      if (!dumpFilter.empty()) {
+        std::string msgName(IPC::StringFromIPCMessageType(aMsg->type()));
+        if (msgName.find(dumpFilter) != std::string::npos) {
+          dumpIPCMessageToFile(aMsg, mIPCDumpCount);
+          mIPCDumpCount++;
+        }
+      } else {
+        dumpIPCMessageToFile(aMsg, mIPCDumpCount);
+        mIPCDumpCount++;
+      }
     }
 
     // Not the trigger message. Output additional information here for